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One of the lessons that evolution teaches us is that you really shouldn’t release alien species onto remote, isolated islands (or other such isolated habitat). This is because 1) these places often contain unique species that have evolved to fit their particular, often predator-free locale. And 2) newly introduced species, finding abundant prey and few of their own predators, are likely to run amok, quickly adapting to local conditions and killing everything in sight. If you care about biodiversity, keep the aliens away.

Unfortunately, we’ve got this kind of problem on our hands in the South Atlantic. While the victims of the feast are not some flightless, defenseless animal that’s been living in paradise too long, they are mostly dependent on one particular island for nesting, meaning that the sudden predation they’re suffering could threaten them with extinction. And the best part is, the perpetrators are… house mice! Mice that have quickly evolved to 3 times their normal size, and have recently started taking on prey that is much, much larger than themselves, acting extremely aggressive and voracious. If not for the threat this poses to endangered sea birds, this would actually be cool. Here is the story :

“Gough Island hosts an astonishing community of seabirds and this catastrophe could make many extinct within decades,” said Dr Geoff Hilton, a senior research biologist with Britain’s Royal Society for the Protection of Birds (RSPB).

“We think there are about 700,000 mice, which have somehow learned to eat chicks alive,” he said in a statement.

The island is home to 99 percent of the world’s Tristan albatross and Atlantic petrel populations — the birds most often attacked. Just 2,000 Tristan albatross pairs remain.

“The albatross chicks weigh up to 10 kg (22 lb) and … the mice weigh just 35 grams; it is like a tabby cat attacking a hippopotamus,” Hilton said.

The house mice — believed to have made their way to Gough decades ago on sealing and whaling ships — have evolved to about three times their normal size.

This is a common phenomenon on island habitats — for reasons much debated among scientists — where small animal species often grow larger while big species such as elephants display “dwarfism” and become smaller.

In the case of the mice of Gough Island, their remarkable growth seems to have been given a boost by a vast reservoir of fresh meat and protein.

AGONISING DEATH

The rapacious rodents gnaw into the bodies of the defenseless and flightless chicks, leaving a gaping wound that leads to an agonising death. Scientists say once one mouse attacks the blood seems to draw others to the feast.

While predation by oversized mice is unusual, birds on small islands are especially vulnerable to extinction from human activities such as the introduction of alien species.

This is because many birds that have evolved on isolated islands with no predators have become what biologists term “ecologically naive” — meaning they do not recognize danger from other animals.

The image of rapacious packs of killer house mice devouring prey which dwarfs them in size is really too much. I don’t think I’ll be sleeping well tonight.

Update: In comments, nihilan was nice enough to point out that Nature News has an article on this as well, with a video of the carnage.

Commenters are responsible for the content of comments. The opinions expressed in articles, linked materials, and comments are not necessarily those of PandasThumb.org. See our full disclaimer.

“Was this “quick evolution” to 3 times their normal size through random mutations and natural selection?”

Of course it was through genetic variation and natural selection (some of the alleles leading to larger size may already have been present in the population, at low levels, or new mutations could have occured - probably did - but further study would be required to determine that with precision). Are you suggesting that some supernatural entity magically made the mice larger, so that they could attack baby seabirds?

Failure to answer this post will be construed as inability to come up with an answer, and refusal to honestly admit it.

We don’t know that albatross chicks experience agony. Certainly we experience agony when we project ourselves onto the chicks and imagine what it is like for them, but that’s not the same thing. The nature of the conceptual world of non-humans – or whether there is one in any meaningful sense – remains an open question, and is likely to remain one for a long time, perhaps forever.

In fact, the Mauseturm was for centuries the Mautturm, or Toll Tower. It was burned down by the French in 1689, but restored by the King of Prussia in 1855 in the Neo-Gothic style and served as a signal tower for the narrow passage until 1974, when the channel was deepened. Since then, the Mauseturm has been inhabitied by bats and legends – and, perhaps, a mouse or two.

Was this “quick evolution” to 3 times their normal size through random mutations and natural selection?

My discussion includes a couple of assumptions, but I think they are reasonable ones:

Arrival of whaling ships in South Atlantic–before 1850 (the zenith of American whaling was around 1846). So mice could have arrived on the island 155 years ago (or earlier–there was substantial exploration in the South Atlantic quite early in the Age of Discovery–mice conceivably could have arrived as early as the 1400s-1500s ).

House mouse generations per year–apparently female mice can bear young at age five to seven weeks. Gestation is just shy of 20 days. Norwegian rats, which are bigger, take a few days longer. To account for the bigger size of these mice, let’s take the rat figure of 24 days (although it would be interesting to know whether the gestation period has actually increased, whether the additional size is obtained post-partum or not, etc.).

Combining gestation (three-plus weeks) and sexual maturity (five to seven weeks), let’s call a generation slightly more than ten weeks or, for convenience, five per year.

Hmmm. That gives us five x 155 or 775 mice generations since the first mice colonized the island. Minimum. In human terms, that would take us back to the end of the last Ice Age.

700,000 mice! That’s a pretty robust population for one small island. Competition for limited resources must be, literally, savage. The likelihood of an occasional favorable mutation and the opportunity for fixation sound pretty good with those demographics.

Time enough for a bit of “micro” evolution, wouldn’t you agree, Blast?

You are correct. In fact, I was going to make another post in the interest of accuracy, but no-one seemed interested in Bishop Hatto.

There were two historical bishops of Mainz named Hatto. This is from memory, but…the earliest was in the eighth or early ninth century, and known to have been extremely unpopular. The second was in the tenth century, and believed to have been less unpopular. The legend is usually said to apply to the second one, but this is believed by some historians to be an unfair incidence of confusion.

At any rate, the tower in the picture is certainly unlikely to date from either the eighth of the tenth century. The fact that it is round, alone, makes that very unlikely. It’s just a toursim site.

It’s unlikely that mediaeval mice actually ate a living human being; I was just reminded of the legend by the post. Anyone else who checked the link got that it was a joke. It’s conceivable that an unpopular figure went unburied, and partially eaten by mice, for some period of time. They were less fastidious then. Don’t forget the “synod horrifica”, at which the cadaver of pope Formosus was dug up and “put on trial”.

I had thought that I understood why you were accusing me of “ignoratio elenchi” (the definition at the link you provided is identical to the one at the link I provided). Perhaps you though I was arguing that “religion is not incompatible with science BECAUSE this would make religious people feel excluded from science”. This would indeed be logically incorrect, and arguably an example of ignoratio elenchi. But I’m making two seperate, logically unrelated, statements.

1) Claiming that someone’s religion is incompatible with science, when they feel otherwise is a way of attempting to exclude them from science (if they want to initiate the claim on their own that’s different). But this alone wouldn’t be an argument that science isn’t compatible with religion. It’s just a fact.

Also,

2) Independantly, many people who know something about religion feel that in many forms, it is compatible with science…

Your claim is that you don’t want to exclude religious people from from science, but that you do want to tell them that their religion is incompatible with science. It is you who is in a position which is logically difficult to defend.

We donâ€™t know that albatross chicks experience agony. Certainly we experience agony when we project ourselves onto the chicks and imagine what it is like for them, but thatâ€™s not the same thing. The nature of the conceptual world of non-humans â€” or whether there is one in any meaningful sense â€” remains an open question, and is likely to remain one for a long time, perhaps forever.

By similar logic I can’t know thay you experience agony, only that I would under similar circumstances.

As far as I am concerned, if the brain structure, chemistry, and electrical activity are similar enough, and the resulting behavior is similar enough, then “agony” can be inferred. The mind/brain problem is solved by realizing that there is no “mind” that is distinct from the brain.

Re “Does anybody have any clues as to what kind of selection pressures on this island caused the mice to grow so large?”

No clues, but I have a guess. In fights among themselves, larger ones would have an advantage. Otoh, when it comes to evading larger predators, small ones may be better at hiding, which may be what keeps them from getting larger in mainland ecosystems. In the absence of other size related pressures, I’d think that would do it.

Your claim is that you don’t want to exclude religious people from from science, but that you do want to tell them that their religion is incompatible with science. It is you who is in a position which is logically difficult to defend.

It is you who seem not to have the foggiest idea of what logic is, and cannot distinguish between empirical and normative statements. The claim that religion is incompatible with science – in the sense that they make conflicting claims – is empirical; I make the claim because I believe it to be true, and I won’t be bullied into not saying it by your assertions as to the consequences on science education of saying it – claims which I find dubious. OTOH, what you claim is a “corollory (sic)” – that I want religious people excluded from science – is a normative statement that has nothing to do with the empirical statement. It’s not a view I hold, nor do I think it’s a view that anyone holds. And it is downright stupid to claim that there is any basis in logic by which I must hold such a view.

Of course it was through genetic variation and natural selection (some of the alleles leading to larger size may already have been present in the population, at low levels, or new mutations could have occured - probably did - but further study would be required to determine that with precision). Are you suggesting that some supernatural entity magically made the mice larger, so that they could attack baby seabirds?

I quite agree with your evaluation; but, if the alleles are already present, then how can that be called evolution? My point here is simply that whenever change in morphology occurs, it’s termed “evolution”–with no questions seemingly being asked. As you stated, “further study” is required. But either way, this isn’t what you would classicly call the kind of “slow, gradual” change that Darwin would insist upon.

My sense is that there is just a simple interaction taking place between the environment and the genetic capacity of the mice, a simple trigger mechanism that involves genes that are normally suppressed ( one probably regulating growth hormone, as Steve Reuland noted in a late post. But, of course, the gene for the growth hormone remains unaffected in this scenario). I see this as demonstrating that organisms have an innate, powerful adaptive capacity. That’s how I would design them!

harold wrote:

Failure to answer this post will be construed as inability to come up with an answer, and refusal to honestly admit it.

I wouldn’t be sent to the cloakroom, would I? :)

Stevepinhead wrote:

Time enough for a bit of “micro” evolution, wouldn’t you agree, Blast?

This is a double-edged sword. If mice can change so dramatically (both structurally and behaviorally) in so short a time, then how is it that mice have remained relatively the same over millions of years? http://mbe.oxfordjournals.org/cgi/content/full/1… that is, the problem of stasis.

I quite agree with your evaluation; but, if the alleles are already present, then how can that be called evolution?

Because that is what evolution is. “Evolution” refers to the heritable change in characteristics of a population of organisms. Change in an allele frequency in a population is clearly a change in a heritable characteristic of that population. (Don’t forget that the origin of a new allele is also a change in allele frequency: p(t) = 0, p(t+1) > 0.)

I suggest that, if you want to refer to someting other than that, then you need to use a term other than “evolution.”

By similar logic I can’t know thay you experience agony, only that I would under similar circumstances.

I mean “know” in the usual empirical sense of belief strongly justified by evidence and reason. It wouldn’t be reasonable to expect one human (me) to lack a capacity for agony shared by humans on the basis of common human physiology and behavior, including verbal behavior – it’s a matter of Occam’s Razor. But we don’t have that sort of information about albatross chicks; they have a different set of physiological responses, and in particular they lack language.

As far as I am concerned, if the brain structure, chemistry, and electrical activity are similar enough, and the resulting behavior is similar enough, then “agony” can be inferred.

How similar is “similar enough”? To deny it for me would simply be obstinacy, but the same isn’t true of albatross chicks.

The mind/brain problem is solved by realizing that there is no “mind” that is distinct from the brain.

The mind is what the brain does. But the mind/brain problem isn’t at issue here. Perhaps you mean the other minds problem, since you introduced that in the first quote, but that isn’t really at issue either. I wasn’t making a metaphysical comment, I was referring to real empirical differences between humans and other species. See, e.g., http://instruct.westvalley.edu/lafave/dennett_an…

“I quite agree with your evaluation; but, if the alleles are already present, then how can that be called evolution?”

Because that IS evolution. New mutations produce new genetic variability, but the genetic variability already present in the population, or genetic variability that arises from recombination of alleles during sexual reproduction, can also be acted on by natural selection. Both are still evolution.

I didn’t suggest that new mutations necessarily WEREN’T part of this mouse evolution, either. A period of 150 years is many, many mouse generations. Some new mutations will have arisen within (not necessarily remained in) that mouse population, that’s a guaranteed fact, that’s chemistry. But new mutations may or may not be crucial to the change in size. Nobody knows yet.

“My point here is simply that whenever change in morphology occurs, itâ€™s termed â€œevolutionâ€â€”with no questions seemingly being asked.”

Well, again, change in morphology across generations in a lineage IS evolution. It’s evolution no matter what the mechnanism; even a hard core young earth creationist admits that chihuahuas had wolf ancestors and these mice had smaller mice as ancestors. That’s the FACT or OBSERVATION of evolution.

What the THEORY of evolution does is explain a scientific mechanism for how such changes occur. Genetic variability, which we now understand at the molecular and biochemical level (of course there’s always a lot more to learn, thank goodness), usually in concert with natural selection. For significant adaptive, directional changes in morphology (such as seen with these mice), natural selection is effectively a requirement.

The theory of evolution absolutely does not “rule out” direct supernatural intervention in every single case, any more than any other scientific theory does, or ever can, for that matter. What it does do, is provide a natural explanation of what we observe, which can be verified empirically, and accepted by people of a wide variety of philosophical and religious backgrounds.

“As you stated, â€œfurther studyâ€ is required.”

Absolutely, to determine with more precision exactly what happened in this case.

“But either way, this isnâ€™t what you would classicly call the kind of â€œslow, gradualâ€ change that Darwin would insist upon.”

First of all, this isn’t fair to Darwin - he didn’t insist that all evolutionary change must be slow in this sense. It’s making a straw man of his views. In fact, the famous “Darwin’s finches” show similar levels of morphologic change over similar time spans (evolutionarily speaking), and he used them as an example. Darwin would certainly agree that these mice evolved.

Second of all, we know a great deal more about biology than Darwin did, and so even if he “would have been wrong” about some specific problem, it means little. We know vastly more physics than Gallileo did, but we don’t disdain the contributions of Gallileo.

CONTINUED BELOW….

My sense is that there is just a simple interaction taking place between the environment and the genetic capacity of the mice, a simple trigger mechanism that involves genes that are normally suppressed ( one probably regulating growth hormone, as Steve Reuland noted in a late post. But, of course, the gene for the growth hormone remains unaffected in this scenario). I see this as demonstrating that organisms have an innate, powerful adaptive capacity. Thatâ€™s how I would design them!

Was this â€œquick evolutionâ€ to 3 times their normal size through random mutations and natural selection?

Were the super-mice intelligently designed and then dropped down from Heaven?

Hey, since you’re back now, maybe you’d like to answer some questions for me.

*ahem*

YOU are the one who wrote:

Goldschmidt noted that the total amount of DNA within cells of lower and higher animals is roughly the same, and he speculated that all of the information for all of the proteins that organisms need are to be found in this DNA materialâ€”it just simply gets shifted about. I think the implications for ID are rather clearâ€¦..but, of course, if I am forced to spell it all out for you, I can.

*I* called your loudmouthed bluff by responding:

Please do. In as much detail as possible. Dontâ€™ skip any steps.

I very much prefer it whehn IDers make specific statements that can be tested, rather than waving their arms about vague assertions such as â€œtranspeciationâ€ and â€œchromosomal changesâ€.

Please tell us precisely what you think happens during speciation, and precisely why it indicates that there is a designer at work in any stage of the process. Please be as precise, detailed and complete as possible.

What does the designer do, precisely, in your view.

What mechanisms does it use to do whatever the heck you think it does.

Where can we see these mechanisms in action today.

Iâ€™ve been asking for DAYS now to see a scientific theory of ID. hereâ€™s your chance. Right in front of the whole world.

The floor is all yours.

Well, Blast, whatâ€™s the problem here. YOU offered to tell em all about it; *I* took you up on your offer.

Wassamatter, is your mouth just bigger than your balls?

Any time you are ready to live up to your own words and â€œspell it out for meâ€, Iâ€™m waiting.

I quite agree with your evaluation; but, if the alleles are already present, then how can that be called evolution?

Um, because “evolution” is defined as “a change in allele FREQUENCIES over time”.

I am still awaiting your explanation of hbnow “frontloading: works. Along wiht your explanation of where I can see chlorophyll genes in any animal, or genes for rattlesnake venom in any cobra, or ANY example of frontloaded genes. Any at all. A-N-Y.

Third of all, this change took place over many mouse generations, so it isn’t necessarily all that “slow”. The only meaningful sense of the term “slow” in this context is with regard to the rate of things that impact on evolution, such as intensity of natural selection, mouse reproduction rate, level of genetic and phenotypic variability in the population at any given arbitrary time, and so on.

“My sense is that there is just a simple interaction taking place between the environment and the genetic capacity of the mice, a simple trigger mechanism that involves genes that are normally suppressed ( one probably regulating growth hormone, as Steve Reuland noted in a late post. But, of course, the gene for the growth hormone remains unaffected in this scenario).”

I’m not sure exactly what you are saying here. If you are saying that individual mice can adapt to and respond to their environment, to some degree, that’s certainly true, especially for a mammalian genus like mice. That’s a different type of “adaptation”. This type of adaptation or environmental response in an individual, such as gain or loss of body fat or muscle mass, development of immunity to an infectious agent, growth of extra fur as a response to temperature or diurnal cues, etc, is a non-evolutionary source of change in an individual. Of course, individuals have these adaptive systems because of evolution, in the first place. At any rate, this type of adaptation doesn’t explain why current mice are much larger than their ancestors.

You may also be arguing for a reasonable but discredited hypothesis of evolution, known as “Lamarckism” (a reference, some say unfair, to a great French biologist actively slightly earlier than Darwin). In essence, you may be saying that ancestor mice “knew” or “perceived” or “experienced”, in some way, that larger size would be an advantage, and that as a result, their germ cell DNA changed, in just the right way, to include genetic basis for larger size for their offspring. This view was initially discredited on theoretical grounds, because it provides no mechanism. How could the experience of the parent mouse change the DNA sequence in its germ cells, IN JUST THE RIGHT WAY? For that matter, if mice have this power, why stop at becoming slightly larger? Later, this view was empirically discredited as well.

Individual adaptation does not explain the evolution of these mice over generations. Lamarckism does not explain it in a scientifically satisfying way. The theory of evolution DOES explain it.

“I see this as demonstrating that organisms have an innate, powerful adaptive capacity.”

Some organisms have a lot of adaptive capacity at the level of the individual (eg humans). Some do not. All have limits in terms of the adaptive capacity of one individual to the surrounding environment.

Evolution causes populations to adapt to environments in a powerful way, across generations (although it can also cause them to go extinct).

“That’s how I would design them!”

It’s nice if you feel, personally, that life turned out just the way you would have designed it, but that’s irrelevant. Others argue that life is very different from what THEY would have designed.

Why would you design the mice to attack the baby seabirds, and NOT design the seabirds to an advantage over the mice? The theory of evolution does not lead to this dilemma.

It looks as if you have a lot of posts to address. Just take it slowly.

t.s.

“The claim that religion is incompatible with science â€” in the sense that they make conflicting claims â€” is empirical; I make the claim because I believe it to be true, and I wonâ€™t be bullied into not saying it”

The empirical observation that SOME religions make claims that directly conflict with science is absolutely correct.

To conclude from this that ALL religions are directly incompatible with science is an elementary example of flawed logic. It is quite literally the same as arguing that “some men are Greeks so all men are Greeks”.

“by your assertions as to the consequences on science education of saying it â€” claims which I find dubious. OTOH, what you claim is a â€œcorollory (sic)â€ â€” that I want religious people excluded from science â€” is a normative statement that has nothing to do with the empirical statement.”

Not in the slightest. I made, and make, an empirically testable, non-normative, conjecture about human behavior. If scientists and science educators routinely declare that all religious traditions are incompatible with science, religious people will be excluded from science, at the very least at a psychological and social level. This is not a normative statement, it could be true whether I feel that this would be a good thing or a bad thing or a neutral thing.

The best way for you to disprove it would be empirically - show me, with convincing laboratory or field data, that when students are told by scientists and science educators that their religious beliefs conflict with science, even if they and their clergy say otherwise, that this does NOT create an atmosphere of exclusion.

YOU attach normative value to this conjecture.

“Itâ€™s not a view I hold, nor do I think itâ€™s a view that anyone holds.”

I have repeatedly acknowledged that you, personally, don’t want to exclude religious people from science.

“And it is downright stupid to claim that there is any basis in logic by which I must hold such a view.”

However, you do express a strong emotional desire to repeatedly state that all religion is incompatible with science, even religions whose clergy and adherents feel otherwise.

This is a view which, if expressed by someone presumed to be a scientific authority, could make religious people feel excluded from science. Yet you do not wish to exclude religious people from science. Thus, a logical dilemma presents itself.

The easiest way out of this dilemma would be to restrict claims that religion is incompatible with science to those specific religious positions which do, overtly conflict with science. You could still critique the ethical or logical claims of other religions, as well, just not by reference to a non-existent conflict with science.

You insist on continuing to dig your dishonest lying hole. I pointed out before that a) you’re obsessed with me and b) there are more constructive things you could do. I honestly don’t give a flying … about the content of your comments on this subject, which are steeped in dishonesty and irrationality. As I said before, I will continue to make critical comments about religion whether you like it or not. And there are no “logical dilemmas” that prevent me from doing so.

Do you guys have to derail every thread with a religion vs. science debate? Not that there aren’t appropriate places for that, but it doesn’t have much to do with mutant killer mice, which are awesome.

Does anybody have any clues as to what kind of selection pressures on this island caused the mice to grow so large?

It seems that the default selective pressure in most species is towards larger sizes. In other words, absent any selection pressure to the contrary, the larger members of most species will be the most successful, presumably because of being able to outcompete their conspecifics for mates and territory. The factors which work against this are the scarcity of food (bigger animals have to eat more), and in smaller organisms, predation (bigger animals are more likely to be caught).

Since these mice have found a new niche that provides lots of calories and protein, and since they’re probably more or less predator free, it’s no surprise they’re getting bigger. It may also be that larger mice are better able to attack these baby chicks than the smaller mice.

If you watch the video, it actually appears that the chick feels nothing. Of course, I don’t know that.

Acutually, the chick does seem to be responding to the mice attacks. Not very much, but there’s definitely signs of irritation, if nothing else. What it’s definitely not doing is fighting back. It could easily peck at the mice, scream for its mommy, or move around to keep the sore spots covered. It seems strange that it doesn’t.

My guess is that the chick’s behavioral instincts are to hold perfectly still when under threat. This would work against hawks and eagles, which are probably the only predators they would have been exposed to over the last several millienia, but would be useless against mice. It would be cool if the birds evolve new behavioral defenses, if they’re not wiped-out first.

You’re right of course. As you’ll note, one of us HAS made a number of posts about the evolution of giant mutant killer mice.

As for ts, I think his final words on the subject tell us everything we need to know…

“You insist on continuing to dig your dishonest lying hole. I pointed out before that a) you’re obsessed with me and b) there are more constructive things you could do. I honestly don’t give a flying … about the content of your comments on this subject, which are steeped in dishonesty and irrationality. As I said before, I will continue to make critical comments about religion whether you like it or not. And there are no “logical dilemmas” that prevent me from doing so.”

As you’ll note, one of us HAS made a number of posts about the evolution of giant mutant killer mice.

As you’ll note, Harold introduced the science vs. religion “debate” in his response to my post about the Hatto tower. But he is living such a lie that he can’t acknowledge such plain truths, and must change the subject.

I didn’t read Blast’s speculation about a switch being turned on or off as necessarily suggesting that an individual mouse in its individual lifetime generates a “somatic” response which is then somehow transmitted to its offspring (i.e., Lamarckism).

On the other hand, Blast may indeed have been making one more trip to the old “front-loading” well, as Lenny suspects.

That doesn’t necessarily mean he’s wrong in this particular case, though, although being right almost certainly has different implications for evolution than Blast might wish.

A good deal of phenotypic variation in animals is modulated by genetic “switches,” if by this WE mean (whatever Blast means…) that the variation results from changes in cis-regulatory regions and signalling genes, rather than in protein-coding genes.

This, there could well be existing potentials for a range of non-“normal” sizes in mice that are, in their usual environment, suppressed by networks of regulatory and signalling genes. A relatively minor change to a network of this kind might lift the suppression on an existing growth hormone (or permit it to act longer, or at different points in development and maturation) without any need for the mice to evolve a new or different growth hormone.

This would be a testable hypothesis. If it turned out to explain some part of this picture, it would not, of course, validate Blast’s poorly-articulated ID-drenched “front-loading” theories. It would merely reinforce one standard and well-understood means by which animals adapt to meet new selective pressures.

Well, I may have misunderstood Blast’s comments. He sounded like he might be proposing what I took to be a Lamarckist explanation - that the mouse’s “need” for larger size DIRECTED germ cell genetic sequences in some way.

In some expressions of classic Lamarckism, the phenotype of the parent adapts as well. Guy gets big muscles working at the docks, and his germ cells magically carry genes for bigger muscles to his kids, so to speak. But I’m not sure if the infamous giraffes were ever supposed to actually develop longer necks from stretching. They just sense a “need” to reach higher leaves, and made an effort, and their kids are born with longer necks.

I guess it comes down to the definition of the somewhat inexact and historically inaccurate, but still useful, term, “Lamarckism”. I think of it as meaning the idea that the germ cells of the parent are genetically modified in a DIRECTED way, to “deliberately” make the offspring more adapted. With or without somatic morphologic adaptation of the parents.

(No doubt a certain humorless poster will obsessively draw our attention to some arbitary dictionary definition of Lamarckism that “proves me wrong”, and refer to me as a “liar”.)

“This, there could well be existing potentials for a range of non-“normal” sizes in mice that are, in their usual environment, suppressed by networks of regulatory and signalling genes. A relatively minor change to a network of this kind might lift the suppression on an existing growth hormone (or permit it to act longer, or at different points in development and maturation) without any need for the mice to evolve a new or different growth hormone.”

This is an extremely plausible explanation. This would be a straight case of mutation and natural selection. The minor change you mention being a mutation in a regulatory gene.

Another thing that could have happened, and these things are not at all exclusive, is that existing alleles in the original mouse population (relevant to the growth regulation systems you mention), could have been sufficient for larger body size, when in the right combination, and expressed in the right environment. And the selection of larger mice could have led to more and more mice with allele combinations for big size. Eventually, alleles correlated with smaller body size would become very rare, and very unlikely to occur in a homozygous state or together in the same genome.

An argument in favor of this second type of mechanism playing a role is that, as has been noted by previous posters, body size change is a common and rapid evolutionary adaptation (and it happens both ways). On the other hand, a lot of investigations of the molecular basis of evolutionary adaptations seem to uncover a mutation. That example of cats not having a sweet detecting protein is a good one (it’s a minor adaptation, but they save energy, and possibly avoid maladaptive behaviors, by not having it).

Actually, Harold, I think your hypothesis is the more likely one–that there is a range of alleles in mouse genes affecting size in the current “mainland” mouse population, and that this existing pool of variation is probably sufficient to support the increase in size in the “island” mice. Something similar was suggested by the post about the size that lab mice can attain (“working” in a lab is also a new niche that mice can exploit without the usual constraints on their size encountered in the wild).

Of course, as several have pointed out, a change in allele frequency is still evolution.

I was simply suggesting that–stripped of its “front-loading” dross–Blast had (for a change) actually suggested a plausible–if perhaps not the most likely–mechanism for these observations. And one that, as you have also emphasized, perfectly consistent with current evo-devo science.

I didn’t read Blast’s speculation about a switch being turned on or off as necessarily suggesting that an individual mouse in its individual lifetime generates a “somatic” response which is then somehow transmitted to its offspring (i.e., Lamarckism).

On the other hand, Blast may indeed have been making one more trip to the old “front-loading” well, as Lenny suspects.

Fortunately for Blast, _Mus musculus_ is one of the species that has had its entire genome completely sequenced.

So, it should be a snap for Blast (with all his, uh, “study of evolution” – snicker, giggle) to simply go to that complete sequenced genome, point to the sequence that he thinks was “frontloaded”, and SHOW IT TO US.

Probably that’s why there’s gonna be a slight hold-up: Blast is still digging through the human genome, trying to find the switch that will grant him access to the “Instant Understanding of Genetics Without Having to Study” stretch of DNA (hint, Blast, it’s in one of the junk sections).

I’m sure that, as soon as Blast achieves instant karma, he’ll start in on Mickey and Minnie and let us know…

qetzal,
Re “It sounds like [Blast] predict they will find some pre-existing ‘switch’ that was flipped in the island mice, allowing them to grow larger. […] but no evidence of any switch-like mechanism.”

Question - couldn’t the changing of a base pair to a different one be regarded as a “switch”?

On the topic of rapid evolution, see “New animal species evolved in an instant”, a New Scientist report on a new sort of fruit maggot living exclusively on Asian honeysuckle, but which seems to be a hybrid of other species which are found only on blueberries & snowberries.

then let me ask you this: if I take a few Great Danes and end up with a couple of chihuahuas, would you agree that some “alleles” likely have changed (at least in terms of expression/repression). Now, do you really want to call that change “evolution”?}}

The answers would be yes and yes.

{{If you are going to argue that a changed environment has led, through Darwinian mechanisms, to this morphological change. then you are faced with the difficulty of explaining why the mouse has remained essentially the same for 14 million years. This is a two-edged sword. Also, if Darwinian adaptation can happen so quickly, why do species go extinct?

There are dozens of mouse species which vary greatly in size and morphology, and while I haven’t looked at a mouse cladogram lately, I’m pretty sure that many of them have evolved in the last 14 million years. It’s not as if there is one “mouse” type that doesn’t vary.

And the reason why all mice aren’t huge is because selective pressure normally keeps them small, something that was implied in the original article.

Modern-day biologists are much more open to what might traditionally be characterized as a Lamarckian interpretation.

Actually, no, very few (if any) biologists take Lamarkian evolution seriously. There is no good evidence that it even happens and no known mechanism to explain it if it did.

To end this extremely lengthy post, I return to the original question: why, if there is some morphological change in an organism, must evolution be invoked like a knee-jerk reaction?

It’s not being invoked in a knee-jerk fashion (perhaps that’s a bit of projection on your part.) It’s being invoked because this is what we observed to happen. The mice evolved. They changed. Their population is decidedly different than their founder population. That’s what evolution is.

Now if what you’re really talking about is natural selection, the fact is that it’s a well-studied process that has been observed occurring under controled conditions, and it’s the only known mechanism to explain this increase in size. As I said earlier, changes in size like this aren’t that hard to evolve; you can evolve them through artificial selection in a very short time. And field studies have witnessed such evolution, and in some cases (like the Grants’ work on Darwin’s finches) the selective pressures can be rigorously quantified.

When a big thunder cloud starts pouring rain on people, we don’t normally invoke the supernatural. This is a mundane process requiring no special explanation beyond what meterologists have already figured out. Same too with these mice.

then let me ask you this: if I take a few Great Danes and end up with a couple of chihuahuas, would you agree that some “alleles” likely have changed (at least in terms of expression/repression). Now, do you really want to call that change “evolution”?}}

The answers would be yes and yes.

I’m actually shocked by your answer–the second one. You take what is patently artificial selection and call it evolution. My head is spinning. With your answer, as far as I’m concerned, you’ve emptied the word ‘evolution’ of any meaning.

Steve Reuland wrote:

(Evolution is) being invoked because this is what we observed to happen. The mice evolved. They changed.

This just simply solidifies what I just said: to equate ‘evolution’ to ‘change’ renders the former meaningless. As I mentioned in my posts, Goldschmidt could produce “pseudocopies” of certain animals simply by altering the temperature during development. Blacks are morphologically different from Caucasians and from Asians. Which “evolved” from which? Which is “higher” than the other?

I’m six-inches taller than my dad and a foot taller than my mom. Did I ‘evolve’ from them? I’m obviously a ‘larger’ species. (I’m not just trying to nitpick here; I just think your use of the word ‘evolution’ doesn’t distinguish in any way between these ‘changes’ and normal variation in a stable species, to say nothing of what is normally understood to be evolution: i.e., transpeciation–moving across the species boundary.)

Steve Reuland wrote:

And field studies have witnessed such evolution, and in some cases (like the Grants’ work on Darwin’s finches) the selective pressures can be rigorously quantified.

Speaking of Darwin’s finches, the Grants’ study show the SAME finches growing larger or smaller beaks depending on environmental conditions (wet/dry). Now which form is the species form, and which is the ‘evolved’ form. In other words, if they easily alternate between forms, then which came first,the chicken or the egg?

Actually, no, very few (if any) biologists take Lamarkian evolution seriously. There is no good evidence that it even happens and no known mechanism to explain it if it did.

I didn’t say biologists are “taking Lamarkian evolution seriously.” I said they are more open to Lamarkian interpretations. Maybe you’re not part of that trend.

The mice evolved. They changed….That’s what evolution is.

Now if what you’re really talking about is natural selection, the fact is that it’s a well-studied process that has been observed occurring under controled conditions, and it’s the only known mechanism to explain this increase in size.

I’m beginning to see that I concede too much in saying that microevolution occurs. You then seem to think that RM+NS is what produces all adaptation. No one has proven beyond doubt that mutations (changes) are random. Mutations might be directed, organized, the result of a built-in potential of the organism. This is what seems to occur with Darwin’s finches, and apparently happens with the common mouse. You say that natural selection is a “known mechanism”, and yet you can’t tell me in any kind of detail at all what has happened to cause this mouse to enlarge and to change its habits. What has triggered this response? What mutations have exactly taken place? What does the genome look like before and after? I know these are tough questions that science still needs to explore, but to say evolution is a “known mechanism” is overstating things. We know that organisms change. Evolution is a theory; that’s all.

Steve Reuland wrote:

When a big thunder cloud starts pouring rain on people, we don’t normally invoke the supernatural. This is a mundane process requiring no special explanation beyond what meterologists have already figured out. Same too with these mice.

To compare the complexity of living things to a thunder cloud is just plain hubris. I don’t make this remark lightly. The more I study science, the more I come to realize just how little science really knows. Everything we know–as profound as it may be–is only a superficial understanding of deeper realities. When it comes to biology, this is even more so the case. Rather than acknowledging the mountain of understanding that remains to be climbed, you seem to be happy just to give the mountain a name–evolution.

Blast, it’s really not that hard, honest. These processes are all part of a continuum. I know that the “slippery slope” inherent in that makes you very nervous, but breathe deep and try really hard this time:

Various well-understood mechnisms generate variation, even in species with “stable” phenotypes established in stable environments. That you ARE phenotypically different from your parents is one example and expression of that accumulating variation.

When the environment begins to shift–and that’s not just changing temperatures, or climate, but changes in the behavior of any of the other critturs in the environment, including humans and including breeding pressures–then distinctive subpopulations can begin to develop and, if the shifts and changes are persistent or disruptive enough–speciation can occur.

Call it “microevolution” if that helps you to wrap your mind around the beginning of the process. But before proclaiming that it can’t lead to speciation, or that speciation–viewed from hundreds of millions of years of further cycles of replication, variation, selection, and speciation–can’t lead to different lineages and even different body plans, please explain IN DETAIL why–if the changes and pressures continued long and forcefully enough–any of these processes would necessarily hit some “invisible” and inexplicable Wall or Stop Point What observed facts, principles, or processes preclude or prohibit ongoing change.

In short, Blast, you may be right that the mice or the finches or (your old standby) Goldschmidt’s exemplars contain a fair amount of intraspecific variability–that they may just be trembling on the verge of speciating, approaching and retreating, but not really crossing some human-imposed definitional line–but WHY, if those same pressures were cranked up a little higher, for a little longer, do you imagine that the process could not go slightly further, become irreversible?

It’s like the sound barrier, Blast, it’s not really there. Or if you seriously think you have evidence for some “Go No Further” process, please lay it out for us, once and for all: where do we find the invisible evolutionary traffic cops who would blow their whistles and constrain the process inside the ruts you wish for?

Blast, it’s really not that hard, honest. These processes are all part of a continuum. I know that the “slippery slope” inherent in that makes you very nervous, but breathe deep and try really hard this time:

Various well-understood mechnisms generate variation, even in species with “stable” phenotypes established in stable environments. That you ARE phenotypically different from your parents is one example and expression of that accumulating variation.

When the environment begins to shift–and that’s not just changing temperatures, or climate, but changes in the behavior of any of the other critturs in the environment, including humans and including breeding pressures–then distinctive subpopulations can begin to develop and, if the shifts and changes are persistent or disruptive enough–speciation can occur.

Call it “microevolution” if that helps you to wrap your mind around the beginning of the process. But before proclaiming that it can’t lead to speciation, or that speciation–viewed after hundreds of millions of years of further cycles of replication, variation, selection, and speciation–can’t lead to different lineages and even different body plans, please explain IN DETAIL why–if the changes and pressures continued long and forcefully enough–any of these processes would necessarily hit some “invisible” and inexplicable Wall or Stop Point? What observed facts, principles, or processes preclude or prohibit ongoing change?

In short, Blast, you may be right that the mice or the finches or (your old standby) Goldschmidt’s study critturs contain a fair amount of intraspecific variability–that they may just be trembling on the verge of speciating, approaching and retreating, but not quite crossing some human-imposed definitional line–but WHY, if those same pressures were cranked up a little higher, for a little longer, do you imagine that the process could not go slightly further, become irreversible?

It’s like the sound barrier, Blast, it’s not really there.

Or, if you seriously think you have evidence for some “Go No Further” process, please lay it out for us, once and for all: where do we find the invisible evolutionary traffic cops who would blow their whistles and constrain the process inside the ruts you wish for?

I’m beginning to see that I concede too much in saying that microevolution occurs. You then seem to think that RM+NS is what produces all adaptation. No one has proven beyond doubt that mutations (changes) are random. Mutations might be directed, organized, the result of a built-in potential of the organism.

Blast, no one will ever prove beyond doubt that all mutations are random. Surely you realize that no one can prove a universal negative. You completely miss the point here.

Virtually all studies indicate that mutations are random, in the sense of undirected, and within the limits of any given study to determine. I am aware of a few controversial studies with bacteria, that some people argued might show evidence of something like directed mutation. I don’t believe that interpretation held up, but I admit I haven’t looked into it recently. Regardless, the vast, vast majority of evidence indicates mutations are not directed.

The clear, overwhelmingly uncontroversial scientific conclusion is that mutations are random (i.e. undirected). And there’s no scientific reason to invoke directed mutation until and unless someone presents compelling evidence that it happens. No one has.

This is what seems to occur with Darwin’s finches, and apparently happens with the common mouse.

Based on what evidence? I suggest there is none. Can you provide any?

You say that natural selection is a “known mechanism”, and yet you can’t tell me in any kind of detail at all what has happened to cause this mouse to enlarge and to change its habits. What has triggered this response? What mutations have exactly taken place? What does the genome look like before and after? I know these are tough questions that science still needs to explore, but to say evolution is a “known mechanism” is overstating things. We know that organisms change. Evolution is a theory; that’s all.

This objection makes no sense. No one (that I have seen) is claiming to actually know the molecular &/or allelic changes that led to increased size in these mice. All anyone has done is to try to explain the mechanisms that evolutionary theory predicts are likely to be involved. Remember, that’s what scientific theories are for! They allow us to make confident predictions even before we have the critical data. That’s what’s so valuable about theories, and that’s what you so casually (& wrongly) dismiss when you say evolution is “just” a theory.

Those predictions are based on a long and detailed history of similar predictions that have been correct. That’s why we call evolution a theory, not a hypothesis, and it’s why we can make confident predictions about these mice.

Now, you can argue that we don’t know that evolution really explains this situation. And you’re right. We don’t - yet. But we do know that evolution happens, and evolution can explain this. Directed mutation can also explain it, but since we’ve never observed that to happen, there’s no good scientific reason to favor that over evolution.

Puh-leeze, Blast. Your quotes from Goldschmidt came from a website run by some nutcake who calls himself a “philosopher and ecological visionary”. And you never even HEARD of Waddington or Baldwin until *I* told you about them. Just like you never heard of _Caudipteryx_. Or _Pakicetus_.

Don’t bullshit us about your, uh, extensive study of science, Blast. What you know about science could fit comfortably on the back of a postage stamp. If you drew lots of pictures.

Iâ€™m actually shocked by your answerâ€”the second one.Â You take what is patently artificial selection and call it evolution.Â My head is spinning.Â With your answer, as far as Iâ€™m concerned, youâ€™ve emptied the word â€˜evolutionâ€™ of any meaning.

I’m sorry, but I am not the one who gets to determine what evolution is and isn’t. Evolution is defined as a change in the allele content of a population over time. That is what evolution is. If you think it’s something else, then you are simply ignorant.

I presume that you’re thinking of evolution as some sort of change in “kind”, past some barrier that supposedly exists between species. I hate to break it to you, but this is largely a creationist contrivance, and is contrary to the way in which biologists think about living things. Biologists do not see barriers between species, they see a fine continuum of organisms throughout time broken only by extinction.

This just simply solidifies what I just said: to equate â€˜evolutionâ€™ to â€˜changeâ€™ renders the former meaningless.Â

Not just change, but long-term genetic change. If that makes the term “meaningless” to you, it’s because you don’t know what evolution is.

As I mentioned in my posts, Goldschmidt could produce â€œpseudocopiesâ€ of certain animals simply by altering the temperature during development.Â

Which are obviously not heritable, and therefore do not count as evolution.

Blacks are morphologically different from Caucasians and from Asians.Â Which â€œevolvedâ€ from which?Â Which is â€œhigherâ€ than the other?

Neither one evolved from the other, both evolved from a common ancestor. And it is meaningless to speak of one being “higher” than the other. This is a throwback to early 20th century thinking; you are somewhat behind the times here.

Iâ€™m six-inches taller than my dad and a foot taller than my mom.Â Did I â€˜evolveâ€™ from them?

Â

Individuals do not evolve, populations evolve. Evolution is a population level phenomenon.

I don’t mean to be rude, but the above demonstrates that you lack even so much as a basic, highschool understanding of evolution. You’re going to have to learn the fundamentals, and disabuse yourself of some horrendous misconceptions, before it becomes worthwhile to discuss this with you further.

Iâ€™m obviously a â€˜largerâ€™ species.Â (Iâ€™m not just trying to nitpick here; I just think your use of the word â€˜evolutionâ€™ doesnâ€™t distinguish in any way between these â€˜changesâ€™ and normal variation in a stable species, to say nothing of what is normally understood to be evolution: i.e., transpeciationâ€”moving across the species boundary.)

What you think is “normally” understood to be evolution is a gross misunderstanding on your part. Speciation is obviously an important evolutionary phenomenon, but evolution and speciation are not synonymous. Any change in a population’s allele content is evolution. It happens all the time, constantly, with every generation.

Speaking of Darwinâ€™s finches, the Grantsâ€™ study show the SAME finches growing larger or smaller beaks depending on environmental conditions (wet/dry).Â Now which form is the species form, and which is the â€˜evolvedâ€™ form.Â In other words, if they easily alternate between forms, then which came first,the chicken or the egg?

Speaking of “form” like this is a throwback to typological thinking – biologists have long rejected such thinking, because there are no identifiable platonic “types” or “forms” or “kinds”. There are merely interbreeding populations, and they are diverse. That diversity provides the raw material through which directional change can occur, as was seen with the finches. That is what evolution is.

I didnâ€™t say biologists are â€œtaking Lamarkian evolution seriously.â€Â I said they are more open to Lamarkian interpretations.Â Maybe youâ€™re not part of that trend.

I can asure you, there is no such trend.

Iâ€™m beginning to see that I concede too much in saying that microevolution occurs.Â You then seem to think that RM+NS is what produces all adaptation.Â

It is the only known mechanism of adaptive evolution, and a very powerful mechanism at that. I’ll be happy to accept any other as soon as someone can demonstrate it working.

No one has proven beyond doubt that mutations (changes) are random.Â

Mutations are random with respect to fitness (not necessarily random in an absolute sense), and there is abundant evidence to support this. The fact that most mutations are harmful, and cause any number of diseases, is a pretty good indicator that they’re not being “directed”.

Mutations might be directed, organized, the result of a built-in potential of the organism.

There is no evidence that this occurs, and no mechanism to explain it even if it did. It is pure vitalistic nonsense.

This is what seems to occur with Darwinâ€™s finches, and apparently happens with the common mouse.

Â

No, the Grants were able to demonstrate that changes in size occurred directionally from preexisting variation. There is no known inborn “trigger” of change, or any other such nonsense.

You say that natural selection is a â€œknown mechanismâ€, and yet you canâ€™t tell me in any kind of detail at all what has happened to cause this mouse to enlarge and to change its habits.

Â

Since I wasn’t there to witness the change, painstakingly recording every detail of every mouse like the Grants did with Darwin’s finches, I obviously can’t tell you in detail what the selective pressures were.

I could give you a perfectly reasonable account of what I assume the selective pressures were, based on what we know from similar cases, but given that this is what the original article did, it would be redundant on my part.

[What has triggered this response?Â What mutations have exactly taken place?

Â

There is no “response” that was triggered; you are again thinking backwards. It is simply a matter of larger mice being more successful and having more offspring.

As for mutations involved, I would assume that a regulatory region which controls the levels of growth hormone received one or more point mutations that weren’t present in the founder population. Of course I have no way of knowing unless I were to study the mice in detail, but it’s not important. We know that the changes were heritable, and we know that size is the sort of thing that can evolve fast. There is always variation within any population and continual mutations are always expanding that variation outwards, so this is about the most mundane example of evolution one could find

What does the genome look like before and after?

Â

Pretty much the same minus a few point mutations.

To compare the complexity of living things to a thunder cloud is just plain hubris.Â I donâ€™t make this remark lightly.Â

I wasn’t comparing their complexity. It’s hard for me to believe that this misunderstanding on your part is unintentional.

I was making an analogy based on your claim that evolution is being invoked in a “knee jerk” fashion for these mice. Of course it isn’t. Evolution by natural selection is a mundane process that’s been observed occurring many, many times. When you have a known mechanism to explain something, you don’t go off inventing complicated, unknown mechanisms that have never been observed to happen. You have been arguing that since we can’t “rule out” some other mechanism affecting this change, that we shouldn’t conclude that it was evolution by natural selection. Sorry, but this kind of reasoning is stupid. It’s every bit as stupid as saying that we can’t conclude that a rain shower was caused by thunder clouds because we can’t rule out the possibilty of a 1000 foot giant having pissed on us.

The more I study science, the more I come to realize just how little science really knows.

I don’t mean to sound rude, but you have shown here that you lack an elementary level understanding of evolution; I have little doubt that your knowledge of biology in general suffers the same.